The Sun Earth Moon System
Planet Earth
Shape Spherical Oval shaped
West to east* Rotation Fifteen degree /hour* Rotation is just less than 24 hours Magnetic field North and south magnetic poles Protect the earth from solar wind*
Earth s revolution* Earth s orbit around the sun Shape is elliptical 365.25 days Closest to the sun on January 3 Farthest from the sun on July 4
Tilt of the Earth* Tilts on its axis 23.5 degrees This tilt of the earth is what causes the seasons
Equinox* Autumnal Equinox 9/22 or 9/23 Spring Equinox 3/20 or 3/21
Solstice* Summer 6/21 or 6/22 Winter 12/21 or 12/22
Quiz 1. How much does the earth tilt on its axes? 2. What direction does the earth rotate? 3. When is the earth closest to the sun? 4. What season does the solstice start when the sun is pointing at the tropic of cancer? 5. Which equinox starts the first day of Spring?
Space object nearest to earth Romans called it Luna which means shining From the word Luna we get the word lunar, which refers to the moon The moon
Features of the moon Diameter 3,476 km in diameter Distance from earth - 384,400 km Gravity 1/6 that of earth Moon s motion Moon revolves around the earth in 27 1/3 earth days* Moon rotates on its axis 1 moon day = 27 1/3 earth days*
Phases of the moon The moon is ½ illuminated most of the time (except during a lunar eclipse) The moon phases we see depend on how much of the illuminated side we see, not on how much is illuminated* The moon revolves from west to east at 13 o / day This causes the moon to come up 50 minutes later each 24 hour period*
Phases of the Moon The movement of the earth and moon are the reason the moon appears to have phases The names of the moon phases using the (DOC)* Method New moon the moon is between the sun & earth Waxing Crescent moon First Quarter is ½ of the moon showing Waxing Gibbous Full Waning gibbous Last quarter Waning crescent
Phases of the Moon
Eclipses The result of shadows cast by the earth and the moon There is a main shadow and a partial shadow The main shadow is the umbra* The partial shadow is the penumbra*
Lunar eclipse When the mood moves into the earth s shadow Umbra The moon is darkened The moon looks like a copper red disc The red tone of the moon is caused by the atmosphere of the earth bending the sun rays
Lunar Eclipse
Solar Eclipse when the earth moves into the moons shadow Solar eclipse is longest at the equator 7.5 minutes When the sun shines through Deep valleys on the moon, during a solar eclipse, beads or string of bright light form and are called Bailey s Beads Partial eclipses are more common than total eclipses
Solar Eclipse
Eclipses How can an object the size of the moon cover an object the size of the sun?\ The sun is 400 times larger than the moon Sun diameter 1 392 000 km Moon s diameter 3 476 km The sun is also 400 times farther away Sun s distance from earth 149,000,000 km Moon s distance from earth 384,400 km
Lunar Surface and composition Surface solid rock covered with dust The moon has no atmosphere Because of no atmosphere temperatures vary from 130o C to 170oC in the shadows Moon s crust is 1 to 300 km thick Pieces of rock from space bombard the surface since there is no atmosphere to burn up those things falling toward its surface.
Craters The results of the meteorites hitting the surface of the moon 30,000 named craters on the moon Copernicus is 91 km from rim to rim
The moon plain is called Maria (the dark areas) Maria is Latin for sea Maria is formed from hardened lava Lunar Surface Lunar Highlands (the light areas) mountains formed from huge chunks of rock hitting the moons surface Mountains are as high as 5 km above the moons surface
Moons composition Rocks brought from the moon by Apollo astronauts show composition much like earth Moon s crust oxygen, silicon aluminum, Iron, calcium Moon dust is much like our sand
Origin of the moon Appears to be the same age as earth No signs of past life One theory is moon another planet pulled in by earth s gravity Another theory is that the moon and earth formed from the same dust within gravitational pull. Another theory is that during earth s formation a piece was flung free from the earth Impact theory- collision of mars sized object with earth